<?php

/**
  * Backup class, Backup.php
  * AdminBackup
  * @category classes
  *
  * @author Andrew Brampton
  * @copyright Andrew Brampton
  * @license http://www.opensource.org/licenses/osl-3.0.php Open-source licence 3.0
  * @version 0.1
  *
  */

class Backup
{
	/** @var integer Object id */
	public $id;
	
	/** @var string Last error messages */
	public $error;

	/**
	 * Creates a new backup object
	 *
	 * @param string $filename Filename of the backup file
	 */
	public function __construct( $filename = NULL )
	{
		if ( $filename )
			$this->id = self::getBackupPath($filename);
	}

	/**
	 * Get the full path of the backup file
	 *
	 * @param string $filename Filename of the backup file
	 * @return The full path of the backup file, or false if the backup file does not exists
	 */
	public static function getBackupPath($filename)
	{
		$backupdir = realpath( PS_ADMIN_DIR . '/backups/' );

		if ( $backupdir === false  )
		{
			die ( Tools::displayError('Backups directory does not exist') );
		}

		// Check the realpath so we can validate the backup file is under the backup directory
		$backupfile = realpath( $backupdir . '/' . $filename );
		if ( $backupfile === false OR strncmp($backupdir, $backupfile, strlen($backupdir)) != 0 )
		{
			die ( Tools::displayError('Hack attempt') );
		}

		return $backupfile;
	}
	
	/**
	 * Get the URL used to retreive this backup file
	 *
	 * @return The url used to request the backup file
	 */
	public function getBackupURL()
	{
		$adminDir = __PS_BASE_URI__.substr($_SERVER['SCRIPT_NAME'], strlen(__PS_BASE_URI__) );
		$adminDir = substr($adminDir, 0, strrpos($adminDir, '/'));

		return $adminDir . '/backup.php?filename=' . basename ($this->id);
	}

	/**
	 * Delete the current backup file
	 *
	 * @return boolean Deletion result, true on success
	 */
	public function delete() {
		if ( !$this->id || !unlink ( $this->id ) )
		{
			$this->error = Tools::displayError('Error deleting') . ' ' . ($this->id ? '"' . $this->id . '"' : Tools::displayError('Invalid ID'));
			return false;
		}

		return true;
	}

	/**
	 * Deletes a range of backup files
	 *
	 * @return boolean True on success
	 */
	public function deleteSelection($list) {
		foreach ($list as $file) {
			$backup = new Backup($file);
			if (!$backup->delete())
			{
				$this->error = $backup->error;
				return false;
			}
		}
		return true;
	}
	
	/**
	 * Creates a new backup file
	 *
	 * @return boolean true on successful backup
	 */
	public function add()
	{
		if ( _DB_TYPE_ !== 'MySQL' )
		{
			$this->error = Tools::displayError('Sorry, backup currently only supports MySQL database types. You are using') . ' "' . _DB_TYPE_ . '"';
			return false;
		}

		// Generate some random number, to make it extra hard to guess backup file names
		$rand = dechex ( mt_rand(0, min(0xffffffff, mt_getrandmax() ) ) );
		$date = time();
		$backupfile = PS_ADMIN_DIR . '/backups/' . $date . '-' . $rand . '.sql';

		// Figure out what compression is available and open the file
		if (function_exists('bzopen'))
		{
			$backupfile .= '.bz2';
			$fp = @bzopen($backupfile, 'w');
		}
		else if (function_exists('gzopen'))
		{
			$backupfile .= '.gz';
			$fp = @gzopen($backupfile, 'w');
		}
		else
			$fp = @fopen($backupfile, 'w');

		if ($fp === false)
		{
			echo Tools::displayError('Unable to create backup file') . ' "' . addslashes($backupfile) . '"';
			return false;
		}

		$this->id = realpath($backupfile);

		fwrite($fp, '/* Backup for ' . $_SERVER['HTTP_HOST'] . __PS_BASE_URI__ . "\n *  at " . date($date) . "\n */\n");

		// Find all tables
		$tables = Db::getInstance()->ExecuteS('SHOW TABLES');
		$found = 0;		
		foreach ($tables as $table)
		{
			$table = current($table);

			// Skip tables which do not start with _DB_PREFIX_
			if (strlen($table) < strlen(_DB_PREFIX_) || strncmp($table, _DB_PREFIX_, strlen(_DB_PREFIX_)) != 0)
				continue;

			// Export the table schema
			$schema = Db::getInstance()->ExecuteS('SHOW CREATE TABLE `' . $table . '`');

			if (count($schema) != 1 || !isset($schema[0]['Table']) || !isset($schema[0]['Create Table']))
			{
				fclose($fp);
				$this->delete();
				echo Tools::displayError('An error occur while backing up. Unable to obtain the schema of').' "'.$table;
				return false;
			}

			fwrite($fp, '/* Scheme for table ' . $schema[0]['Table'] . " */\n");
			fwrite($fp, $schema[0]['Create Table'] . ";\n\n");
		
			$data = Db::getInstance()->ExecuteS('SELECT * FROM `' . $schema[0]['Table'] . '`');

			if (count($data) > 0)
			{
				// Export the table data
				fwrite($fp, 'INSERT INTO `' . $schema[0]['Table'] . "` VALUES\n");

				foreach ($data as $i => $row)
				{
					$s = '(';
					foreach ($row as $field => $value)
						$s .= "'" . mysql_real_escape_string($value) . "',";
					$s = rtrim($s, ',');

					if ($i < count($data) - 1)
						$s .= "),\n";
					else
						$s .= ");\n\n\n";
					
					fwrite($fp, $s);
				}
			}
			$found++;
		}
		
		fclose($fp);
		if ($found == 0)
		{
			$this->delete();
			echo Tools::displayError('No valid tables were found to backup.' );
			return false;
		}
		
		return true;
	}
	
}
?>